Definition of grossest:
(adj) :
(of an amount) Excluding any deductions; including all associated amounts.
(n) :
The total amount (of goods, money, etc) before taxes, expenses, exceptions, tares, or similar deductions are subtracted.
(adj) :
(informal, Canada, US, Australia) Causing disgust.
(adj) :
(of behaviour) Highly or conspicuously offensive.
(adj) :
Lacking refinement in behaviour or manner; offending a standard of morality.
(adj) :
(of a product) Lacking refinement; not of high quality.